I’m no electrician, but dealing with an appliance failure by fitting a higher capacity fuse seems like a last-resort admission of incompetence. I was once told by an electrician that fuses or circuit breakers are there, not as people believe, to protect electrical appliances but to protect the building’s wiring. The reported damage to the insulation seems to prove this point! The first electrician’s action seems at best irresponsible and potentially criminal.